Hitherto, there is known a paper sheet processing apparatus including a casing, a placing unit which is provided in the casing so as to place paper sheets thereon, a transport unit which transports the paper sheets taken from the placing unit into the casing, and a plurality of stacking units which stack the paper sheets transported by the transport unit according to each sort and from which stacked paper sheets may be removed (for example, see WO 2008/096429 A).
In a case where a large number of paper sheets are continuously processed in such a paper sheet processing apparatus, the stacking process is stopped once at a time point when each stacking unit is fully filled with the paper sheets or a predetermined number of paper sheets are stacked in the stacking units. Then, the paper sheets are removed from the stacking units, and then the process on the paper sheets is resumed. Furthermore, the removed paper sheets are sent to the next process.
In a case where the operation of removing the paper sheets is frequently performed, an operator may forget the sorts of the paper sheets removed from the stacking units. For example, the operator may forget whether the removed paper sheets are fit notes or unfit notes, or new notes or old notes.